The orange cast on many Seattle streets at night will shift to a white glow over the next six years as the city replaces streetlamps with new LED fixtures. Mayor Greg Nickels announced a plan yesterday to use federal stimulus funds to begin replacing 40,000 of the high-pressure-sodium bulbs with the light-emitting diodes to save money and energy.

“They would save about nine million kilowatt hours and about $408,000 a year,” says Seattle City Light spokesman Scott Thomsen. The power saved would be roughly equivalent to 750 single-family houses, which, he says, use about 12,000 kilowatt hours a year.

Funding to kick start the program comes from a $6.1 million stimulus grant to reduce energy use, including weatherizing buildings and installing energy-efficient products. Of that money, $1 million will go toward the streetlamp program next year, assuming the Department of Energy approves the expenditure this summer. In all, the new streetlamps will cost about $20 million.

The city is already testing several different brands of LEDs in several blocks of the Capitol Hill neighborhood. “People describe it as a little brighter, a little whiter,” says Mike Mann, director for the city’s office of sustainability.

Seattle City Light maintains approximately 84,000 street lights, including 20,000 outside the city limits.

Photo via alykat on Flickr.